Extended sliding mode observer‐based high‐accuracy motion control for uncertain electro‐hydraulic systems

Abstract

In this paper, a novel robust backstepping control strategy is introduced to achieve high‐accuracy tracking performance for electro‐hydraulic servo systems (EHSSs) without velocity information in the presence of uncertainties and disturbances. Firstly, system dynamics of the studied EHSS considering parameter deviations, modeling errors, and unknown external loads which are grouped into lumped mismatched and matched disturbances in the mechanical system and pressure dynamics, respectively, are developed. On the basis of the sliding mode theory, two extended sliding mode observers (ESMOs) are originally established to simultaneously estimate the immeasurable angular velocity of the actuator, and lumped mismatched and matched uncertainties. As a consequence, an observer‐based controller is designed using the conventional backstepping technique to ensure a highly accurate tracking position control. In addition, the stability of the observer and overall closed‐loop control system is conclusively proven through the Lyapunov theory. Finally, several numerical simulations for an EHSS with a hydraulic rotary actuator are conducted to demonstrate the advantage of the recommended method compared to the existing well‐known extended state observer‐based control approaches.

A Position Controller for Hydraulic Excavators With Deadtime and Regenerative Pipelines

“…Our previous controller [14], overviewed in Section II-D, was also derived from the sliding-mode controller ( 17), but it is algebraically combined with the plant dynamics model (14a). In contrast, the proposed controller is derived by combining (17) with the PD controller (15a). This difference is beneficial in that the proposed controller is less dependent on the plant dynamics model, which is not usually accurately available, and also in that the influence of the deadtime can be reduced to a certain level by appropriately tuning the PD gains, as has been discussed in, e.g., [16,Section 4.2].…”

“…The use of the PD controller is to realize a certain level of robustness against the deadtime by tuning the gains (cf., e.g., [16,Chapter 4]). The intention for employing a sliding-mode-like controller is to explicitly cope with the force saturations, which is somewhat different from a common aim of using sliding modes to ensure accurate convergence [1], [13], [17], [18]. In addition, the controller is extended to handle a regenerative pipeline in the hydraulic circuit, which is not explicitly taken into account in the quasistatic actuator model.…”

A Walking Trajectory Tracking Control Based on Uncertainties Estimation for a Drilling Robot for Rockburst Prevention

“…A sliding mode controller based on a high-gain observer was designed to improve the control performance [18]. A sliding mode observer-based controller is designed to ensure highly accurate tracking control characteristics [19]. A sliding mode controller is designed to improve the control precision and attenuate the disturbances, including model uncertainties and external disturbances [20].…”

Speed tracking control for electro-hydraulic system considering variable load disturbance

“…A nonlinear parallel control algorithm is developed for an electro-hydraulic actuator to improve the velocity tracking performance for a valve-pump parallel controlled electro-hydraulic actuator under uncertainties and disturbance [20]. A novel robust backstepping control strategy was introduced to achieve high-accuracy tracking performance for electro-hydraulic servo systems without velocity information in the presence of uncertainties and disturbances [21]. Forming speed is one of the key factors affecting the forming performance.…”